Near field recording and reproducing apparatus

Abstract

A magnetic recording and optical readout apparatus and method, wherein a recording and readout head member records and reproduces a signal while moving relatively to a magnetic recording medium. The head member has a magnetic recording head and a readout head in a body. The head member is supported by a suspension so as to contact the medium or to keep a slight distance from the medium by a lifting-up force being generated by air flow, while moving relatively to the medium. A laser beam is radiated from a laser emitting element through a light transmitting hole formed in a light intercepting layer, whose diameter is smaller than the laser beam wavelength of the laser emitting element. By radiating the laser beam through the hole, localized near field electromagnetic waves are generated and reflected at the medium. The reflected electromagnetic waves bear changes of a polarization angle corresponding to the recorded information, which are detected by the readout head to reproduce the signal.

What is claimed as new and is desired to be secured by Letters Patent of the United States is: 
     
       1. A recording and readout apparatus comprising: an applying means for applying only a magnetic field to magnetically record a signal in a magnetic recording medium;   a radiating means for radiating near field electromagnetic waves onto the magnetic recording medium; and   a detecting means for detecting reflected near field electromagnetic waves from the magnetic recording medium to reproduce the signal recorded in the magnetic recording medium.   
     
     
       2. The recording and readout apparatus according to claim 1, wherein the detecting means detects changes in a polarization angle of the near field electromagnetic waves. 
     
     
       3. The recording and readout apparatus according to claim 1, wherein the applying means applies a magnetic field in a direction substantially perpendicular to the magnetic recording medium. 
     
     
       4. A recording and readout method, comprising the steps of: applying only a magnetic field into a plurality of areas of a magnetic layer constituting a magnetic recording medium in an area-by-area manner to record a signal in each area;   irradiating a laser beam to produce and radiate near field electromagnetic waves onto the magnetic recording medium; and   detecting the near field electromagnetic waves reflected from the magnetic recording medium, to reproduce the signal recorded in the magnetic recording medium.   
     
     
       5. The recording and readout method according to claim 4, wherein the step of detecting the near field electromagnetic waves include detecting changes in a polarization angle of the reflected near field electromagnetic waves corresponding to each of the areas.   
     
     
       6. The recording and readout method according to claim 4, wherein the step of applying only a magnetic field to record a signal includes applying only a magnetic field in a direction substantially perpendicular to the magnetic recording medium.   
     
     
       7. A recording and readout apparatus comprising: a head member having a recording head to magnetically record a signal in a magnetic recording medium by applying only a magnetic field and a readout head to reproduce the signal recorded in the magnetic recording medium;   the readout head including a laser beam emitting element, a light shielding layer disposed opposite to the magnetic recording medium and having alight transmitting portion, with a diameter smaller than a wavelength of the laser beam, to which the laser beam is radiated, to produce near field electromagnetic waves; and   a detecting means to detect near field electromagnetic waves reflected from the magnetic recording medium.   
     
     
       8. The recording and readout apparatus according to claim 7, wherein the detecting means detects changes in a polarization angle of the reflected near field electromagnetic waves.   
     
     
       9. The recording and readout apparatus according to claim 7, wherein the recording head records the signal by applying only a magnetic field in a direction substantially perpendicular to the recording medium.   
     
     
       10. The recording and readout apparatus according to claim 7, wherein the detecting means is arranged proximate to the light transmitting portion.   
     
     
       11. A recording and readout apparatus comprising: a head member having a recording head to magnetically record a recording signal in a magnetic recording medium and a readout head to reproduce the signal recorded in the recording medium;   the readout head including a laser beam emitting element, a magnetic slave layer disposed opposite the magnetic recording medium, a light shielding layer formed on a laser beam emitting element side of the magnetic slave layer and having a light transmitting portion with a diameter smaller than a laser beam wavelength of the laser beam, to which the laser beam is radiated, to produce near field electromagnetic waves; and   a detecting means to detect reflected electromagnetic waves from the magnetic slave layer.   
     
     
       12. The recording and readout apparatus according to claim 11, wherein the detection means detects changes in a polarization angle of the reflected electromagnetic waves. 
     
     
       13. The recording and readout apparatus according to claim 11, wherein the electromagnetic waves are evanescent waves. 
     
     
       14. The recording and readout apparatus according to claim 11, wherein the recording head records the signal by applying a magnetic field in a direction substantially perpendicular to the recording medium. 
     
     
       15. A readout apparatus to reproduce information recorded in a magnetic recording medium comprising: a readout head disposed opposite the magnetic recording medium;   the readout head including a laser beam emitting element, a magnetic slave layer disposed opposite the magnetic recording medium, a light shielding layer disposed opposite the magnetic recording medium and having a light transmitting portion smaller than a wavelength of the laser beam, to which the laser beam is radiated, to produce near field electromagnetic waves;   a detecting means to detect near field electromagnetic waves reflected from the magnetic recording medium.   
     
     
       16. The readout apparatus according to claim 15, wherein the detecting means detects changes in polarization angle of the reflected near field electromagnetic waves.   
     
     
       17. The readout apparatus according to claim 15, wherein information is recorded in the magnetic recording medium in a direction substantially perpendicular to the magnetic recording medium. 
     
     
       18. The readout apparatus according to claim 15, wherein the detecting means is arranged proximate to the light transmitting portion.   
     
     
       19. A recording and readout apparatus comprising: a head member having a recording head to magnetically record a signal in a magnetic recording medium by applying only a magnetic field and a readout head to reproduce the signal recorded in the magnetic recording medium;   the readout head including a laser beam emitting element having a light emitting end opposing the magnetic recording medium; and   a detecting means arranged opposite another end of the laser emitting element and to detect light reflected from the magnetic recording medium.   
     
     
       20. The recording and readout apparatus according to claim 19, wherein the detecting means detects changes in a polarization angle of the reflected light.   
     
     
       21. The recording and readout apparatus according to claim 19, wherein a distance between the light emitting end of the laser emitting element and a surface of a recording layer of the recording medium is smaller than a laser wavelength of the laser emitting element. 
     
     
       22. The recording and readout apparatus according to claim 19, wherein the laser emitting element is a semiconductor laser, whose light emitting end surface extends in a width direction of tracks formed on the recording medium. 
     
     
       23. The recording and readout apparatus according to claim 20, wherein the recording head records a signal by a magnetic field having a direction substantially perpendicular to the magnetic recording medium.